class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        if(p==null&&q!=null||p!=null&&q==null){
            return false;

        }
        if(p==null&&q==null){
            return true;
        }
        if(p.val!=q.val){
            return false;
        }
       return isSameTree(p.left,q.left)&&isSameTree(p.right,q.right);

    }
}